Term average propensity to consume Definition: The proportion of income, usually measured as disposable income or national income, used for household consumption expenditures. It is found by dividing consumption by income. The average propensity to consume, abbreviated APC, most often pops up in discussions of Keynesian economics. The average propensity to consume is the average amount of total household income that is devoted consumption expenditures. For closely related information see marginal propensity to consume, average propensity to save, marginal propensity to save, and consumption function.